(a) Field of the Invention
The present invention relates to a liquid crystal display, and in particular, to a liquid crystal display including a compensation film.
(b) Description of the Related Art
A liquid crystal display (“LCD”) includes upper and lower panels having field-generating electrodes, a liquid crystal (LC) layer interposed therebetween, and a pair of polarizing films attached on outer surfaces of the panels. An electric field is generated in the LC layer by applying electric voltages to the field-generating electrodes. The intensity of the electric field is adjusted to control orientations of LC molecules, which determine a polarization of light passing through the LC layer, and the polarizing films convert the polarization of the light into the transmittance of the light, thereby displaying desired images.
A typical LCD includes a common electrode provided on a panel and a plurality of pixel electrodes provided on another panel. The common electrode and the pixel electrode generate electric field for re-arranging LC molecules to control the transmittance of light passing through the panels. The LCD further includes a plurality of thin film transistors (TFTs) for switching voltages applied to the pixel electrodes.
Among the LCDs, a vertically aligned mode LCD aligning the LC molecules vertical to the panels and including crossed polarizers are increasingly preferred because of its high contrast ratio and wide viewing angle.
The LCD has a problem of light leakage from a side view, which deteriorates lateral visibility and narrows lateral viewing angle. The lateral light leakage may be caused by two reasons.
First, although there is no retardation from a front view since light path from the front view coincides with optic axis of the vertically aligned LC layer, the light path from the side view is offset from the optic axis and this results in the retardation and the change of the light polarization to yield light leakage. Second, although the light from the front view experiences crossed polarization axes, the light from the side view experiences obliquely intersecting polarization axes to yield light leakage.
Although the light leakage may be reduced by using compensation films (or retardation films), the compensation films are very expensive to increase the manufacturing cost of the LCD.